沉积相和地质年代对第四纪土动力学参数的影响  

Influence of Sedimentary Facies and Geological Time on Kinetic Parameters of Quaternary Soil

作　　者：梁师俊[1] 陆吉赟 石树中 LIANG Shijun;LU Jiyun;SHI Shuzhong(Zhejiang College of Construction,Hangzhou 311231,Zhejiang,China;Earthquake Agency of Zhejiang Province,Hangzhou 310000,Zhejiang,China)

机构地区：[1]浙江建设职业技术学院,浙江杭州311231 [2]浙江省地震局,浙江杭州310000

出　　处：《地震工程学报》2019年第3期702-709,723,共9页China Earthquake Engineering Journal

摘　　要：依据收集的嘉兴地区原状土样实测数据,研究土的沉积环境和地质年代对土的动剪切模量比和动阻尼比的影响及土的塑性指数分布规律。结果表明沉积相和地质年代对嘉兴第四纪土层的G/Gmax-γ、λ-γ有明显影响。沉积相相同时,地质年代越新,动剪切模量比越大、动阻尼比越小;地质年代相同时,冲湖相沉积土的动剪切模量比最大、动阻尼比最小。最后给出嘉兴地区不同沉积相和地质年代土层的动剪切模量比、动阻尼比推荐值,并分别利用推荐值和实测值基于FLAC3D进行了土层动力响应分析,从反应谱形状、地表峰值加速度、峰值速度和特征周期等方面验证推荐值的适用性,可供工程参考应用。To gain a better understanding of the deformation behavior of Jiaxing Quaternary sedimentary soils, we collected total 34 undisturbed soil samples. The analysis results revealed that the variation characteristics of the normalized dynamic shear modulus ratio ( G/G max ) and damping ratio (λ) with increasing shear strain (γ) are strongly influenced by the sedimentary facies and geological time. For the same sedimentary facies, the more recent the geological time, the larger is the dynamic shear modulus ratio and the smaller is the dynamic damping ratio. For the same geological time, we found the dynamic shear modulus ratio of the alluvial-lacustrine deposit to be largest, and the dynamic damping ratio the smallest. Moreover, we suggest recommended values for the dynamic shear modulus ratios and dynamic damping ratios of soils of different sedimentary facies and geological time in Jiaxing area. Furthermore, we used FLAC 3D modelling software to perform a dynamic response analysis of the soils at one typical engineering site using the recommended and measured values and verified the applicability of the recommended values. These study results can be used as reference in the seismic risk assessments of engineering projects.

关 键 词：第四纪土层 动剪切模量比 阻尼比 沉积相 地质年代 

分 类 号：P315[天文地球—地震学]